On a forum someone said this: "Atheism is not a belief, rather it is the absence of a belief, and it is beliefs which need to be justified." I responded as follows:

Atheism simply describes a "non-theist." Since the word “atheism” is a negative one, meaning “not a theist,” it doesn’t specify much of anything else except that a person who is an atheist is a non-believer. A non-believer in what? When the question is whether a person believes in any God, an atheist is someone who does not believe in any of them. However, I want to add that when the question is whether a person believes in, say Christianity, an atheist is someone who does not believe in the Christian God. Christians themselves were called atheists in the first century C.E. because they did not believe in the gods and goddesses of the Roman Empire, even though they clearly believed in a God. So when I say Christians are atheists with regard to all other gods but their own, I am being accurate by calling them atheists with regard to those other gods, even if they are not atheists with regard to whether any God exists. It depends on the question and the context what the words atheism/atheist mean.

An agnostic will agree with the atheist against all religious accounts, but she will go on to argue against atheism, claiming it can give no sufficiently justifiable account of the natural world either.

I cannot make too much sense of the idea that atheism, in the context of our debates, means a lack of a belief in God. My position is that agnosticism is the default position, the position that merely says, "I don't know" (which can probably best be described as soft-agnosticism). ANYONE WHO LEAVES THE DEFAULT POSITION HAS THE BURDEN OF PROOF, whether it's a theist or an atheist. When faced with the theist claims an atheist denies them. She doesn't merely say, "I don't believe you," for then she would be an agnostic, the default position. An atheist says "there is no god" (again, depending on the question being asked). And the strong atheist claims she knows this with a great deal of assurance while the weak atheist claims she knows this weakly.

So when an atheist says, "there is no God," or "this God does not exist," those are indeed stated beliefs. If it isn't a stated belief then what is it? And all beliefs must be justified sufficiently to the person making the claim. Non-beliefs must be those things we have never heard about or taken a position on.